Mammut is urgently calling for the immediate discontinuation of use and removal of permanently installed quick draws and carabiners in climbing areas. Irrespective of the manufacturer of such equipment, repeated wear can result in the formation of sharp edges capable of damaging or completely severing ropes, even in relatively small falls. Investigations by Mammut have shown that this known problem is actually far more dramatic than previously assumed and represents a very high risk for climbers.

In recent years, it has become increasingly common to install quick draws on overhanging routes in climbing areas. On the one hand, this is intended to make it easier to clip the rope and, on the other hand, to prevent the sometimes laborious removal of the quick draws.

Depending on their position, as a result of friction from climbing ropes when lowering climbers, these quick draws can be worn to a blunt angle resulting in the formation of very sharp edges (see figure 1). The following positions are particularly affected:

• the first belay point (where the belayer stands away from the wall when lowering)

• belay points under a roof/overhang

• off line belay points

Wear is increased by the presence of dirt or sand on the rope. Extremely sharp edges form on carabiners which almost never bear the load of a fall and are rarely used as a turning point. This means that they are never "deburred" (worn to a rounded shape) and razor-sharp edges can develop. Carabiners with a T-profile tend to be more prone to the formation of sharp edges in comparison with round profiles.

In tests in the Mammut standard fall facility on the carabiner shown in figure 1, it was found that a 9.5 mm rope with fall mass of 80 kg severed at a fall height of just 2.7 meters/fall factor of 1.0. The carabiner used had an extremely sharp edge. Previous investigations have also shown that, in practice, friction in the safety chain can result in a fall factor that is significantly higher than the calculated value. In combination with a very sharp carabiner, even very small falls with a fall height of less than a meter can be critical. Several cases of cut ropes without grave consequences are known. Presently this is being researched as a possible reason for a fatal climbing accident in Switzerland.

Will that just boot the ball down the road, in that steels used for climbing are more durable than say 7000 series aluminum, but not infinitely so? Steel also will abrade and develop edges, especially from ropes with lots of dust/grit in them.

Well, as with labrat, the risk to me may be somewhat hypothetical, although not entirely academic. Still, this is simply a generalization of the worn chains/worn links/worn coldshuts problem that is so common, and so commonly disregarded, even if it's so easily avoided.

Even steel 'biners wear out in the gym. Where they're not subjected to weather and grit.
They'll certainly last longer but that also could revive the false belief they won't cut YOUR rope when YOU fall.